Energy Efficient Heating, Ventilation, and Air Conditioning Packages for Existing Residential Buildings

This project demonstrated and evaluated two residential retrofit packages that use advanced technologies to improve single-family building envelopes, indoor air quality, and cooling efficiency. These technologies included a sub wet-bulb evaporative chiller, supply ventilation systems, and building-envelope sealing. Occupant comfort and indoor air quality were also assessed to study the potential benefits of adopting these retrofit packages.

The project team evaluated each technology independently. The evaluation showed mixed results. The sub wet-bulb evaporative chiller performed worse in the field installation than earlier laboratory and modeling studies suggested. The capacity was significantly limited by the air-side performance of the hydronic fan coil systems. Energy modeling indicated that the optimized sub wet-bulb evaporative chiller design showed substantial savings potential for California residential customers, with average cooling savings of 57 percent. With further development, the sub wet-bulb evaporative chiller has potential in the residential market.

The ventilation systems showed improvement in indoor air quality with average carbon dioxide and particulate matter decreasing 2.5 levels to within acceptable ranges relative to the baseline. Advanced controls were most effective in the cooling season when over-ventilating during cooler nighttime periods and avoiding or minimizing ventilation during hot daytime periods.

The aerosol sealing process successfully reduced home air leakage by 64 percent, and in the other case by 37 percent. This result was very impressive considering these were some of the first applications of retrofit sealing using an aerosol-based process.